AfricaArray Field School – Day 4

I got a bit caught up in other things last night, so this is a day late. In any case, on with it!

The day started with “Safety” Sue’s lecture about, well, safety. Most of the stuff is common sense, and a lot of it is relevant to how industry tends to do things. Things like seatbelts, not using cellphones while driving, being aware of ticks, watching for heatstroke, not licking the electrodes of the resistivity system while it is operating, that sort of thing. OK, she did not actually say the last point, but I am pretty sure it is still good advice.
We also went over some of the admin for the field school, in terms of water and food arrangements.

This was followed by a lecture about the rocks of the Witwatersrand Basin by one of the students here at Wits, TJ. He kept to a fairly high-level overview, in order to highlight the different rocks that can be found, as well as some information on the mineralisation in the basin, the most notable of which is obviously gold. He also brought along some rocks from it for us to have a look at.

Core sample from the Wits.

More hand samples.

Following this, we wandered over to the museum, in the depths of the Geoscience building to look at more examples of the different reefs. As an aside, what is it with tea-rooms being in museums? NMMU does it as well, albeit with a much smaller museum.

Looking at Wits rocks in the museum.

In order to help inform some of the forward modelling that we could do, we headed out to get our first geophysical measurements, of magnetic susceptibilities of some of the rocks found on campus. We got a high score of 294 in a folded sandier horizon. Some quartzite, further south, was way lower, about -0.020.

Our high scorer for the day.

The highly susceptible bed.

After lunch, we carried on working on our bids, which are due later today. Also today, we will be getting an overview of broadband seismology, which I am looking forward to.